net/netfilter/xt_connmark.c

   1 /*
   2  *      xt_connmark - Netfilter module to operate on connection marks
   3  *
   4  *      Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
   5  *      by Henrik Nordstrom <hno@marasystems.com>
   6  *      Copyright © CC Computer Consultants GmbH, 2007 - 2008
   7  *      Jan Engelhardt <jengelh@computergmbh.de>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/skbuff.h>
  26 #include <net/netfilter/nf_conntrack.h>
  27 #include <net/netfilter/nf_conntrack_ecache.h>
  28 #include <linux/netfilter/x_tables.h>
  29 #include <linux/netfilter/xt_connmark.h>
  30
  31 MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>");
  32 MODULE_DESCRIPTION("Xtables: connection mark operations");
  33 MODULE_LICENSE("GPL");
  34 MODULE_ALIAS("ipt_CONNMARK");
  35 MODULE_ALIAS("ip6t_CONNMARK");
  36 MODULE_ALIAS("ipt_connmark");
  37 MODULE_ALIAS("ip6t_connmark");
  38
  39 static unsigned int
  40 connmark_tg(struct sk_buff *skb, const struct xt_target_param *par)
  41 {
  42         const struct xt_connmark_tginfo1 *info = par->targinfo;
  43         enum ip_conntrack_info ctinfo;
  44         struct nf_conn *ct;
  45         u_int32_t newmark;
  46
  47         ct = nf_ct_get(skb, &ctinfo);
  48         if (ct == NULL)
  49                 return XT_CONTINUE;
  50
  51         switch (info->mode) {
  52         case XT_CONNMARK_SET:
  53                 newmark = (ct->mark & ~info->ctmask) ^ info->ctmark;
  54                 if (ct->mark != newmark) {
  55                         ct->mark = newmark;
  56                         nf_conntrack_event_cache(IPCT_MARK, ct);
  57                 }
  58                 break;
  59         case XT_CONNMARK_SAVE:
  60                 newmark = (ct->mark & ~info->ctmask) ^
  61                           (skb->mark & info->nfmask);
  62                 if (ct->mark != newmark) {
  63                         ct->mark = newmark;
  64                         nf_conntrack_event_cache(IPCT_MARK, ct);
  65                 }
  66                 break;
  67         case XT_CONNMARK_RESTORE:
  68                 newmark = (skb->mark & ~info->nfmask) ^
  69                           (ct->mark & info->ctmask);
  70                 skb->mark = newmark;
  71                 break;
  72         }
  73
  74         return XT_CONTINUE;
  75 }
  76
  77 static bool connmark_tg_check(const struct xt_tgchk_param *par)
  78 {
  79         if (nf_ct_l3proto_try_module_get(par->family) < 0) {
  80                 printk(KERN_WARNING "cannot load conntrack support for "
  81                        "proto=%u\n", par->family);
  82                 return false;
  83         }
  84         return true;
  85 }
  86
  87 static void connmark_tg_destroy(const struct xt_tgdtor_param *par)
  88 {
  89         nf_ct_l3proto_module_put(par->family);
  90 }
  91
  92 static bool
  93 connmark_mt(const struct sk_buff *skb, const struct xt_match_param *par)
  94 {
  95         const struct xt_connmark_mtinfo1 *info = par->matchinfo;
  96         enum ip_conntrack_info ctinfo;
  97         const struct nf_conn *ct;
  98
  99         ct = nf_ct_get(skb, &ctinfo);
 100         if (ct == NULL)
 101                 return false;
 102
 103         return ((ct->mark & info->mask) == info->mark) ^ info->invert;
 104 }
 105
 106 static bool connmark_mt_check(const struct xt_mtchk_param *par)
 107 {
 108         if (nf_ct_l3proto_try_module_get(par->family) < 0) {
 109                 printk(KERN_WARNING "cannot load conntrack support for "
 110                        "proto=%u\n", par->family);
 111                 return false;
 112         }
 113         return true;
 114 }
 115
 116 static void connmark_mt_destroy(const struct xt_mtdtor_param *par)
 117 {
 118         nf_ct_l3proto_module_put(par->family);
 119 }
 120
 121 static struct xt_target connmark_tg_reg __read_mostly = {
 122         .name           = "CONNMARK",
 123         .revision       = 1,
 124         .family         = NFPROTO_UNSPEC,
 125         .checkentry     = connmark_tg_check,
 126         .target         = connmark_tg,
 127         .targetsize     = sizeof(struct xt_connmark_tginfo1),
 128         .destroy        = connmark_tg_destroy,
 129         .me             = THIS_MODULE,
 130 };
 131
 132 static struct xt_match connmark_mt_reg __read_mostly = {
 133         .name           = "connmark",
 134         .revision       = 1,
 135         .family         = NFPROTO_UNSPEC,
 136         .checkentry     = connmark_mt_check,
 137         .match          = connmark_mt,
 138         .matchsize      = sizeof(struct xt_connmark_mtinfo1),
 139         .destroy        = connmark_mt_destroy,
 140         .me             = THIS_MODULE,
 141 };
 142
 143 static int __init connmark_mt_init(void)
 144 {
 145         int ret;
 146
 147         ret = xt_register_target(&connmark_tg_reg);
 148         if (ret < 0)
 149                 return ret;
 150         ret = xt_register_match(&connmark_mt_reg);
 151         if (ret < 0) {
 152                 xt_unregister_target(&connmark_tg_reg);
 153                 return ret;
 154         }
 155         return 0;
 156 }
 157
 158 static void __exit connmark_mt_exit(void)
 159 {
 160         xt_unregister_match(&connmark_mt_reg);
 161         xt_unregister_target(&connmark_tg_reg);
 162 }
 163
 164 module_init(connmark_mt_init);
 165 module_exit(connmark_mt_exit);